It's true that of the two of them, Solo is by far the superior study of human nature. That Illya had managed as long as he had probably speaks to how often he's watched Solo do exactly what he's doing now.

"Tsch," he mutters, resisting an urge to fold his arms. "You saw enough. Where do you want me for this?" He's not necessarily compromised, but surveillance and backup might be less risky. Still, if the bodyguard gets curious again, Illya wouldn't mind being a distraction. Especially if it involved knocking him out and dragging him into a dark corner somewhere to sleep it off.